1. Field of the Invention
This invention relates to food processing devices and, more particularly, to a device for irradiating foodstuffs with ultraviolet rays for the destruction of bacteria and other microorganisms disposed on the foodstuff.
2. Description of the Relevant Art
It is well known that microorganisms, particularly yeast, mold spores, fungi, and the egg and/or larva of insects, exist on the surface of foodstuffs prior to packaging, and that these microorganisms must be eliminated to avoid spoilage of the foodstuffs or maturing of the insects. This is particularly true with respect to dry foodstuffs, such as nuts and grains.
In conventional sterilization techniques, the foodstuff is bathed in an atmosphere or solution of chemicals that are toxic to the microorganisms, in hopes of eradicating the microorganisms and hence making the product durable and free from insect life. However, the chemicals used may leave a residue, which is ingested by the consumer, and the chemical treatments are not always effective in view of the numerous instances of live or dead insects and mold still encountered in packaged products.
It is well known that ultraviolet radiation, particularly ultraviolet radiation having a wavelength of approximately 260 nm, kills microorganisms and helps in keeping them under control to avoid spoilage of foodstuffs. One method of sterilizing foodstuffs which utilizes this fact includes irradiating air flowing through heat and air conditioning ducts in order to kill floating or suspended bacteria, and directly irradiating air in occupied areas. Another method involves direct irradiation of the product to be protected. This is accomplished by placing a source of ultraviolet radiation into storage coolers and holding rooms, such as meat lockers. Although effective, the ultraviolet radiation poses a health risk to personnel, and hence cannot be used safely in areas where the food process must be manually controlled.
Finally, many mechanisms have been devised which use ultraviolet radiation for the protection of foods, pharmaceuticals, and other products affected by microorganisms. For example, U.S. Pat. No. 2,364,049, issued to D. Bensel, discloses a process for preserving fresh vegetables wherein the vegetables are transported on a conveyor belt and the conveyor belt passes through a surrounding plurality of ultraviolet lamps. Another technique for irradiating foodstuffs is exemplified by U.S. Pat. No. 1,817,936, issued to G. C. Supplee, which discloses an apparatus for irradiating powdered milk solids as the milk solids are transported through a trough and feed screw device or poured through a vertical conduit.